CA2942188A1 - Method for production and use of nanocellulose and its precursors - Google Patents
Method for production and use of nanocellulose and its precursors Download PDFInfo
- Publication number
- CA2942188A1 CA2942188A1 CA2942188A CA2942188A CA2942188A1 CA 2942188 A1 CA2942188 A1 CA 2942188A1 CA 2942188 A CA2942188 A CA 2942188A CA 2942188 A CA2942188 A CA 2942188A CA 2942188 A1 CA2942188 A1 CA 2942188A1
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- Prior art keywords
- fibrils
- nanocellulose
- particles
- nano
- microfibrils
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- 229920001046 Nanocellulose Polymers 0.000 title claims abstract description 30
- 239000002243 precursor Substances 0.000 title claims abstract description 22
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 15
- 239000002245 particle Substances 0.000 claims abstract description 44
- 239000000463 material Substances 0.000 claims abstract description 43
- 238000000034 method Methods 0.000 claims abstract description 41
- 229920002678 cellulose Polymers 0.000 claims abstract description 26
- 210000001724 microfibril Anatomy 0.000 claims abstract description 26
- 239000001913 cellulose Substances 0.000 claims abstract description 25
- 239000000443 aerosol Substances 0.000 claims abstract description 19
- 239000002131 composite material Substances 0.000 claims abstract description 17
- 238000000926 separation method Methods 0.000 claims abstract description 13
- 239000003960 organic solvent Substances 0.000 claims abstract description 9
- 239000007788 liquid Substances 0.000 claims abstract description 8
- 239000004615 ingredient Substances 0.000 claims abstract description 7
- 239000000725 suspension Substances 0.000 claims abstract description 6
- 239000011111 cardboard Substances 0.000 claims abstract description 4
- 239000003973 paint Substances 0.000 claims abstract description 3
- 238000011282 treatment Methods 0.000 claims description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 239000002105 nanoparticle Substances 0.000 claims description 12
- 208000027418 Wounds and injury Diseases 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000002904 solvent Substances 0.000 claims description 9
- 206010052428 Wound Diseases 0.000 claims description 8
- 239000000047 product Substances 0.000 claims description 8
- 239000000835 fiber Substances 0.000 claims description 6
- 239000011148 porous material Substances 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 3
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- 102000004190 Enzymes Human genes 0.000 claims description 2
- 238000007710 freezing Methods 0.000 claims description 2
- 230000008014 freezing Effects 0.000 claims description 2
- 239000011087 paperboard Substances 0.000 claims description 2
- 238000010257 thawing Methods 0.000 claims description 2
- 229920002488 Hemicellulose Polymers 0.000 claims 1
- 230000004913 activation Effects 0.000 claims 1
- 239000012141 concentrate Substances 0.000 claims 1
- 239000000470 constituent Substances 0.000 claims 1
- 239000001814 pectin Substances 0.000 claims 1
- 229920001277 pectin Polymers 0.000 claims 1
- 235000010987 pectin Nutrition 0.000 claims 1
- 239000000123 paper Substances 0.000 abstract description 18
- 230000000694 effects Effects 0.000 abstract description 12
- 230000003014 reinforcing effect Effects 0.000 abstract description 6
- 230000035699 permeability Effects 0.000 abstract description 3
- 238000005265 energy consumption Methods 0.000 abstract description 2
- 235000010980 cellulose Nutrition 0.000 description 24
- 239000000203 mixture Substances 0.000 description 11
- 238000002360 preparation method Methods 0.000 description 11
- 210000001519 tissue Anatomy 0.000 description 10
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 6
- 239000004964 aerogel Substances 0.000 description 6
- 230000012010 growth Effects 0.000 description 5
- 230000005855 radiation Effects 0.000 description 5
- 238000011160 research Methods 0.000 description 5
- 239000007858 starting material Substances 0.000 description 5
- 241000196324 Embryophyta Species 0.000 description 4
- 229920000168 Microcrystalline cellulose Polymers 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 239000012634 fragment Substances 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 230000035876 healing Effects 0.000 description 4
- 239000008108 microcrystalline cellulose Substances 0.000 description 4
- 235000019813 microcrystalline cellulose Nutrition 0.000 description 4
- 229940016286 microcrystalline cellulose Drugs 0.000 description 4
- 238000000399 optical microscopy Methods 0.000 description 4
- 239000010902 straw Substances 0.000 description 4
- 241001478778 Cladophora Species 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 240000008042 Zea mays Species 0.000 description 3
- 235000016383 Zea mays subsp huehuetenangensis Nutrition 0.000 description 3
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 3
- 230000001580 bacterial effect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 230000006378 damage Effects 0.000 description 3
- 230000002255 enzymatic effect Effects 0.000 description 3
- 230000002209 hydrophobic effect Effects 0.000 description 3
- 208000014674 injury Diseases 0.000 description 3
- 235000009973 maize Nutrition 0.000 description 3
- 230000035515 penetration Effects 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- 239000002023 wood Substances 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 229920002749 Bacterial cellulose Polymers 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 241000195493 Cryptophyta Species 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000035508 accumulation Effects 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 239000007900 aqueous suspension Substances 0.000 description 2
- 239000005016 bacterial cellulose Substances 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 210000003850 cellular structure Anatomy 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000012467 final product Substances 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 238000000265 homogenisation Methods 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 239000007943 implant Substances 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 108700005457 microfibrillar Proteins 0.000 description 2
- 238000003801 milling Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 241000894007 species Species 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000029663 wound healing Effects 0.000 description 2
- 241000589220 Acetobacter Species 0.000 description 1
- 239000002028 Biomass Substances 0.000 description 1
- 239000004966 Carbon aerogel Substances 0.000 description 1
- 241000192700 Cyanobacteria Species 0.000 description 1
- 241000032681 Gluconacetobacter Species 0.000 description 1
- 229920001340 Microbial cellulose Polymers 0.000 description 1
- 108010059820 Polygalacturonase Proteins 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- KVBYPTUGEKVEIJ-UHFFFAOYSA-N benzene-1,3-diol;formaldehyde Chemical compound O=C.OC1=CC=CC(O)=C1 KVBYPTUGEKVEIJ-UHFFFAOYSA-N 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 235000013339 cereals Nutrition 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 238000010336 energy treatment Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 108010093305 exopolygalacturonase Proteins 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 238000004108 freeze drying Methods 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000000499 gel Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000000416 hydrocolloid Substances 0.000 description 1
- 239000000017 hydrogel Substances 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000012978 lignocellulosic material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000003701 mechanical milling Methods 0.000 description 1
- 239000013080 microcrystalline material Substances 0.000 description 1
- 238000007431 microscopic evaluation Methods 0.000 description 1
- 239000002121 nanofiber Substances 0.000 description 1
- 235000019895 oat fiber Nutrition 0.000 description 1
- -1 packaging Substances 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920013657 polymer matrix composite Polymers 0.000 description 1
- 239000011160 polymer matrix composite Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
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- 230000002787 reinforcement Effects 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 231100000241 scar Toxicity 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000010907 stover Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 230000017423 tissue regeneration Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
- D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
- D21H11/18—Highly hydrated, swollen or fibrillatable fibres
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
- A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
- A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
- A61L15/28—Polysaccharides or their derivatives
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P17/00—Drugs for dermatological disorders
- A61P17/02—Drugs for dermatological disorders for treating wounds, ulcers, burns, scars, keloids, or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
- C08L1/02—Cellulose; Modified cellulose
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
- D21H11/12—Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/005—Microorganisms or enzymes
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
- D21H25/04—Physical treatment, e.g. heating, irradiating
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L2400/00—Materials characterised by their function or physical properties
- A61L2400/12—Nanosized materials, e.g. nanofibres, nanoparticles, nanowires, nanotubes; Nanostructured surfaces
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
- C08J2301/02—Cellulose; Modified cellulose
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S977/00—Nanotechnology
- Y10S977/70—Nanostructure
- Y10S977/701—Integrated with dissimilar structures on a common substrate
- Y10S977/702—Integrated with dissimilar structures on a common substrate having biological material component
- Y10S977/706—Carbohydrate
Landscapes
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Veterinary Medicine (AREA)
- Public Health (AREA)
- General Health & Medical Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- Materials Engineering (AREA)
- Hematology (AREA)
- Epidemiology (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Microbiology (AREA)
- Nanotechnology (AREA)
- Polymers & Plastics (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Crystallography & Structural Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Composite Materials (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Pharmacology & Pharmacy (AREA)
- Dermatology (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Paper (AREA)
- Materials For Medical Uses (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Inks, Pencil-Leads, Or Crayons (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
Objective of the method is a procedure for production of nanocellulose, where energy consumption and other costs of production are lower than in methods presented previously. It is based on separation of minute particles from cellulose or plant based ingredients by effects of light, thermal energy or water-soluble organic solvents. These particles act as precursors of nanocellulose. After separation they form in dry state aerosol, in liquid media a suspension, and combine to chains, microfibrils and secondarily formed fibrils, which form further networks with each other or with other fibres and fibrils. Applications are based on their action as reinforcing structure in composites, paper, cardboard, paints and other materials, on forming thin-layer films for electrical, electronic and medical applications, or on viscosity, surface and permeability properties.
Description
METHOD FOR PRODUCTION AND USE OF NANOCELLULOSE AND ITS
PRECURSORS
Introduction and state of art Purpose of this invention is a method for production and separation of nanocellulose and its precursors economically and with a small energy consumption, and for their use as such or without separation into pure state. The invention belongs to area of chemical technology-In the following, the term nanocellulose is used to mean cellulose of particle size lower than one micrometer, precursors compounds or components formed in the biosynthesis of nanocellulose, such as elementary fibrils. These particles can be of varying size.and shape. Nanocellulose has been shown to have several useful technical properties for applications on several branches of industries. Central properties deviating from conventional celluloses are high water binding, high viscosity at low concentrations, forming barrier layers for penetration of different materials, surface properties, high specific surface area, absorption and adsorption properties, ability to form aerogels, and high mechanical properties of microcrystalline cellulose. Potential applications have been presented, among others, for paper, cardboard, packaging, composite, electronic, medical, food and cosmetic industries.
Technologies presented for production of nanocellulose have been for their main part based on energy intensive mechanical milling, high pressure homogenization, use of strong acids or alkalies, cryogenic or other freezing, cryogenic milling, grafting of functional groups of atoms, enzymatic treatments, or their combinations. Using millings and homogenization, microfibrillar cellulose (MFC) is obtained. Its fibril diameter has in various preparations been 5 to 100 nanometres, and fibril length from tens of nanometres to several micrometres. The length to diameter ratio varies or cannot be calculated due to difficulties in measurements. With the acidic method, microcrystalline cellulose (MCC) is obtained, where the length to diameter ratio is from 2 to 10.
PRECURSORS
Introduction and state of art Purpose of this invention is a method for production and separation of nanocellulose and its precursors economically and with a small energy consumption, and for their use as such or without separation into pure state. The invention belongs to area of chemical technology-In the following, the term nanocellulose is used to mean cellulose of particle size lower than one micrometer, precursors compounds or components formed in the biosynthesis of nanocellulose, such as elementary fibrils. These particles can be of varying size.and shape. Nanocellulose has been shown to have several useful technical properties for applications on several branches of industries. Central properties deviating from conventional celluloses are high water binding, high viscosity at low concentrations, forming barrier layers for penetration of different materials, surface properties, high specific surface area, absorption and adsorption properties, ability to form aerogels, and high mechanical properties of microcrystalline cellulose. Potential applications have been presented, among others, for paper, cardboard, packaging, composite, electronic, medical, food and cosmetic industries.
Technologies presented for production of nanocellulose have been for their main part based on energy intensive mechanical milling, high pressure homogenization, use of strong acids or alkalies, cryogenic or other freezing, cryogenic milling, grafting of functional groups of atoms, enzymatic treatments, or their combinations. Using millings and homogenization, microfibrillar cellulose (MFC) is obtained. Its fibril diameter has in various preparations been 5 to 100 nanometres, and fibril length from tens of nanometres to several micrometres. The length to diameter ratio varies or cannot be calculated due to difficulties in measurements. With the acidic method, microcrystalline cellulose (MCC) is obtained, where the length to diameter ratio is from 2 to 10.
2 Operations for preparation are usually performed in water suspensions.
Separation of the final product from diluted suspensions is difficult due to the small size of the particles, small difference in density as compared to water, water binding property, and viscosity properties. Due to costs in preparation and separation, cost of the final product has reached levels which has been preventive for intended economical uses.
Development focused on production and applications has during the recent years been active and has led to several pilot and pre-commercial scale units. According to published data, the largest of these, started in 2011, has a capacity of one ton per day.
Production of microfibril cellulose is also possible to perform by separating it from naturally grown Cladophora algae (Ek et al., Cellulose powder from Cladophora sp.
algae. Journal of Molecular. Recognition 11, 263-265, 1998; Mihranyan et al., Rheological properties of cellulose hydrogels prepared from Cladophora cellulose powder. Food Hydrocolloids 21, 267, 2007). Efforts to produce nanocellulose from genetically engineered blue green algae are still in experimental stage (https://cns.utexas.edu/news, 10 April 2013).
Bacterial nanocellulose (BC) can be produced by various species of Gluconacetobacter, (earlier name Acetobacter), or related species. Cellulose material is produced in aerobic cultivations (WO 2005/003366 Al, Polyteclmika Lodzka, 13. January 2005) and can be further prepared and modified by several approaches (Fu et al., Present status and applications of bacterial cellulose-based materials for skin tissue repair.
Materials Science and Engineering C 33, 2995-3000, 2013). Its principal applications have so far been in medical devices, especially for surgical implants and wound and burn healing.
It is biocompatible, can act as scaffold in the growth of tissue and exhibit integration in the tissue. Production costs for such wound healing preparations, as estimated in 2007, were USD 0.02/cm2 (Czaja et al, The Future Prospects of Microbial Cellulose in Biomedical Applications. Biomacromolecules 8 (1) 1-12,). Despite successful clinical results, as reviewed e.g. by Petersen and Gatenholm, (Bacterial cellulose-based materials and medical devices: current state and perspectives. Applied Microbiology and Biotechnology. 91, 1277-1286,2011) use of this material has been very limited.
Reasons are evidently in part high costs in cultivation, separation and handling of it, in part insufficient proofs of the reliability and controllability of the production technique.
Separation of the final product from diluted suspensions is difficult due to the small size of the particles, small difference in density as compared to water, water binding property, and viscosity properties. Due to costs in preparation and separation, cost of the final product has reached levels which has been preventive for intended economical uses.
Development focused on production and applications has during the recent years been active and has led to several pilot and pre-commercial scale units. According to published data, the largest of these, started in 2011, has a capacity of one ton per day.
Production of microfibril cellulose is also possible to perform by separating it from naturally grown Cladophora algae (Ek et al., Cellulose powder from Cladophora sp.
algae. Journal of Molecular. Recognition 11, 263-265, 1998; Mihranyan et al., Rheological properties of cellulose hydrogels prepared from Cladophora cellulose powder. Food Hydrocolloids 21, 267, 2007). Efforts to produce nanocellulose from genetically engineered blue green algae are still in experimental stage (https://cns.utexas.edu/news, 10 April 2013).
Bacterial nanocellulose (BC) can be produced by various species of Gluconacetobacter, (earlier name Acetobacter), or related species. Cellulose material is produced in aerobic cultivations (WO 2005/003366 Al, Polyteclmika Lodzka, 13. January 2005) and can be further prepared and modified by several approaches (Fu et al., Present status and applications of bacterial cellulose-based materials for skin tissue repair.
Materials Science and Engineering C 33, 2995-3000, 2013). Its principal applications have so far been in medical devices, especially for surgical implants and wound and burn healing.
It is biocompatible, can act as scaffold in the growth of tissue and exhibit integration in the tissue. Production costs for such wound healing preparations, as estimated in 2007, were USD 0.02/cm2 (Czaja et al, The Future Prospects of Microbial Cellulose in Biomedical Applications. Biomacromolecules 8 (1) 1-12,). Despite successful clinical results, as reviewed e.g. by Petersen and Gatenholm, (Bacterial cellulose-based materials and medical devices: current state and perspectives. Applied Microbiology and Biotechnology. 91, 1277-1286,2011) use of this material has been very limited.
Reasons are evidently in part high costs in cultivation, separation and handling of it, in part insufficient proofs of the reliability and controllability of the production technique.
3 Another application of BC studied in several research papers has been for composites.
Mechanical properties of its microfibrils are found to be higher than those of nanocellulose from wood (review: Lee et al., On the use of nanocellulose as reinforcement in polymer matrix composites. Composites Science and Technology 105, 15-27, 2014). but production costs are still high to expect industrial applications for this purpose.
Tensile strength of crystalline nanocellulose has been found to be of similar magnitude than metallic aluminium, and its stiffness higher than of glass fibre. High mechanical properties have also been obtained for purified wood based microfibrils or bacterial microfibrils. Attention and expectations has been paid on their possibilities for use as reinforcing fibres in composites. Hundreds of research papers, made using the qualities obtained from the presently available experimental production, have been published and are reviewed by Lee et al. (locus citatus). In the majority of these, nanocellulose content in the composite has been below 20% of weight A substantial reinforcing is achieved starting from a content of 30% upwards, but even at 95% content does not reach levels of purified preparations or levels calculated theoretically.
Reasons found or suspected are low length to diameter ratio of nanoparticles, their agglomeration reducing effective length to diameter ratio, weak or uneven dispersion, incomplete wetting, weak adhesion to the binding material, porosity of the composite obtained, and multiple disturbing effects of residual water. Precondition for improving strength properties of composites is usually regarded to be a length to diameter ratio of above 50 or above 100.
By adding microfibrils to paper fibre mixture, an improving of mechanical properties and reduction of air permeability of paper has been achieved (WO 2013/072550 A2, UPM-Kymmene Corporation, 23. May 2013). The preparation used has been called fibril cellulose, and consisted of "a collection of isolated cellulose microfibrils or microfibril bundles derived from cellulosic material". It has been added to the fibre mixture during the wet stages of the process.
Preparation of aerogels, originally made from inorganic materials or carbon, has recently been able to produce also from cellulosic materials. Methods have been gel formation in water suspension, followed by exchange of solvent, and cryogenic or
Mechanical properties of its microfibrils are found to be higher than those of nanocellulose from wood (review: Lee et al., On the use of nanocellulose as reinforcement in polymer matrix composites. Composites Science and Technology 105, 15-27, 2014). but production costs are still high to expect industrial applications for this purpose.
Tensile strength of crystalline nanocellulose has been found to be of similar magnitude than metallic aluminium, and its stiffness higher than of glass fibre. High mechanical properties have also been obtained for purified wood based microfibrils or bacterial microfibrils. Attention and expectations has been paid on their possibilities for use as reinforcing fibres in composites. Hundreds of research papers, made using the qualities obtained from the presently available experimental production, have been published and are reviewed by Lee et al. (locus citatus). In the majority of these, nanocellulose content in the composite has been below 20% of weight A substantial reinforcing is achieved starting from a content of 30% upwards, but even at 95% content does not reach levels of purified preparations or levels calculated theoretically.
Reasons found or suspected are low length to diameter ratio of nanoparticles, their agglomeration reducing effective length to diameter ratio, weak or uneven dispersion, incomplete wetting, weak adhesion to the binding material, porosity of the composite obtained, and multiple disturbing effects of residual water. Precondition for improving strength properties of composites is usually regarded to be a length to diameter ratio of above 50 or above 100.
By adding microfibrils to paper fibre mixture, an improving of mechanical properties and reduction of air permeability of paper has been achieved (WO 2013/072550 A2, UPM-Kymmene Corporation, 23. May 2013). The preparation used has been called fibril cellulose, and consisted of "a collection of isolated cellulose microfibrils or microfibril bundles derived from cellulosic material". It has been added to the fibre mixture during the wet stages of the process.
Preparation of aerogels, originally made from inorganic materials or carbon, has recently been able to produce also from cellulosic materials. Methods have been gel formation in water suspension, followed by exchange of solvent, and cryogenic or
4 freeze drying (Fischer et al, Cellulose-based aerogels. Polymer 47, 7636-7645, 2006;
Paakk0 et al., Long and entangled native cellulose I nanofibers allow flexible aerogels and hierarchically porous templates for functionalities. Soft Matter 4,2492-2499, 2008;
Heath and Tie!mans, Cellulose nanowhisker aerogels. Green Chem. 12, 1448-1453, 2010). Reinforcing of the structure of aerogel has been found to be possible by binding with resorcinol formaldehyde resins (Tamon et al., Control of mesoporous structure of organic and carbon aerogels. Carbon 36, 1257-1262, 1998) or polyurethane (Fischer et al., locus.citatus). Applications are based to low weight of volume, high porosity, high surface area in regard to weight or volume, and/or stability of the structure.
Important applications presented are electrical and electronic industries, catalysators, heat and sound isolation, and medical industry.
From research in photonics it is known, that irradiation of light can move and transfer small sized particles. Regarding the amount of energy needed to release material from its site, only rough estimates exist, and the phenomenon has not knowingly been used preparatively or industrially.
Method In the research now performed, it has been surprisingly found, that several lignocellulosic parts of agricultural crops already as such contain microfibrillar or microcrystalline cellulose, or materials which are apt to act as their precursors, and their separation or enriching is possible also more economically than by methods available presently. Material used in this research has been principally straw of cereal crops, various botanical parts of maize stover, and tissue paper, but methods used can be also applied to biomass from other non-wood plants and to products or side-streams of other cellulose producing industries, in limited scope also to other cellulose. The method is based on release from these materials of nano-sized particles, in dry state as aerosols, in liquid media as suspensions, by means of light energy, by controlled heating or by solvent treatment. After separating, the particles assimilate to chains, the chains orient with each other and combine forming microfibrils and secondary fibrils.
Pretreatments, when needed, can be physical, dissolving, and enzymatic operations for disintegrating the cellular structure, for removal of inhibiting material layers, or for concentrating the part of material which can be exploited.
In microscopical studies it has now been surprisingly observed, that by focusing strong light on thin diameter cellulose fibrils they start to disintegrate to particles, sizes of
Paakk0 et al., Long and entangled native cellulose I nanofibers allow flexible aerogels and hierarchically porous templates for functionalities. Soft Matter 4,2492-2499, 2008;
Heath and Tie!mans, Cellulose nanowhisker aerogels. Green Chem. 12, 1448-1453, 2010). Reinforcing of the structure of aerogel has been found to be possible by binding with resorcinol formaldehyde resins (Tamon et al., Control of mesoporous structure of organic and carbon aerogels. Carbon 36, 1257-1262, 1998) or polyurethane (Fischer et al., locus.citatus). Applications are based to low weight of volume, high porosity, high surface area in regard to weight or volume, and/or stability of the structure.
Important applications presented are electrical and electronic industries, catalysators, heat and sound isolation, and medical industry.
From research in photonics it is known, that irradiation of light can move and transfer small sized particles. Regarding the amount of energy needed to release material from its site, only rough estimates exist, and the phenomenon has not knowingly been used preparatively or industrially.
Method In the research now performed, it has been surprisingly found, that several lignocellulosic parts of agricultural crops already as such contain microfibrillar or microcrystalline cellulose, or materials which are apt to act as their precursors, and their separation or enriching is possible also more economically than by methods available presently. Material used in this research has been principally straw of cereal crops, various botanical parts of maize stover, and tissue paper, but methods used can be also applied to biomass from other non-wood plants and to products or side-streams of other cellulose producing industries, in limited scope also to other cellulose. The method is based on release from these materials of nano-sized particles, in dry state as aerosols, in liquid media as suspensions, by means of light energy, by controlled heating or by solvent treatment. After separating, the particles assimilate to chains, the chains orient with each other and combine forming microfibrils and secondary fibrils.
Pretreatments, when needed, can be physical, dissolving, and enzymatic operations for disintegrating the cellular structure, for removal of inhibiting material layers, or for concentrating the part of material which can be exploited.
In microscopical studies it has now been surprisingly observed, that by focusing strong light on thin diameter cellulose fibrils they start to disintegrate to particles, sizes of
5 which are on the resolution limit of optical microscopy. The particles are moving on their sites and can also separate from the plant tissue. After a delay, particles start to separate from the material. At the beginning, this separation can be observed as surface elevation, foam or aerosol. The particles move initially in the direction of the releasing light beam, later directed by local air flow and hinders for it, or by physical forces leading to adsorption or absorption.
The phenomenon can be weakly observed already caused by diffuse daylight, and depends on the intensity of the light. It is found to be affected by infrared, visible and ultraviolet light radiation, and also by thermal energy. This energy can also be produced from other electromagnetic energy sources such as microwave, radio frequency, or ohmic heating. Due to the known disintegration of cellulose by heat, temperature of treatment can be at the highest 180 C.
When the illumination continues and the local temperature elevates, residual moisture evaporates and is removed in the form of droplets or vapour. Small fragments of the material illuminated or heated can be separated simultaneously, follow along this particle flow, and are separated by gravity. Release of particles not observable by optical microscopy continues after this stage, and is observed as vibration of the macroscopic particles, diminution of the surface where light is focused, as accumulation of aerosol in its proximity, and as formation of new microfibrils on areas where particles are accumulated. The smallest particle type observable by optical microscopy is of club-like shape having a hydrophobic tail, of 30 to 100 nm in diameter, the other end being oval and hydrophilic. These particles are later called visible precursors.
Additionally, ball-shaped particles or droplets of 0.5 to 3 pm in diameter are separated.
In microscopic studies it has been found, that these droplets have a multi-layered wall formed by the said visible precursors. In the innermost layer, visible precursors are oriented their hydrophilic ends inwards, in the next ones alternatively outward or
The phenomenon can be weakly observed already caused by diffuse daylight, and depends on the intensity of the light. It is found to be affected by infrared, visible and ultraviolet light radiation, and also by thermal energy. This energy can also be produced from other electromagnetic energy sources such as microwave, radio frequency, or ohmic heating. Due to the known disintegration of cellulose by heat, temperature of treatment can be at the highest 180 C.
When the illumination continues and the local temperature elevates, residual moisture evaporates and is removed in the form of droplets or vapour. Small fragments of the material illuminated or heated can be separated simultaneously, follow along this particle flow, and are separated by gravity. Release of particles not observable by optical microscopy continues after this stage, and is observed as vibration of the macroscopic particles, diminution of the surface where light is focused, as accumulation of aerosol in its proximity, and as formation of new microfibrils on areas where particles are accumulated. The smallest particle type observable by optical microscopy is of club-like shape having a hydrophobic tail, of 30 to 100 nm in diameter, the other end being oval and hydrophilic. These particles are later called visible precursors.
Additionally, ball-shaped particles or droplets of 0.5 to 3 pm in diameter are separated.
In microscopic studies it has been found, that these droplets have a multi-layered wall formed by the said visible precursors. In the innermost layer, visible precursors are oriented their hydrophilic ends inwards, in the next ones alternatively outward or
6 inward. This structure prevents or retards evaporation of water, unless sufficient energy is available to generate vapour pressure to break this structure, releasing simultaneously said visible precursors.. Precursors can also be separated from the ball shaped particles or water droplets or from the original lignocellulosic plant material by treatments with water-soluble organic solvents such as ethanol, methanol or acetone, based on removal of water, often more rapidly than by heating.
Without binding to any possible mechanism, the observations given in the paragraph above indicate, that the key mechanism of this method is removal of bound water from plant tissues or accumulations contaning nanocellulose or its precursors. It is commonly known, that removal of the residual moisture, about 2%, from lignocellulosic materials is extremely difficult using conventional drying methods. Nanocellulose is commonly known to have high water retention capacity. Prolonged heating, infrared radiation, microwave radiation and water soluble organic solvents, have each a good ability to water removal and have now been found to induce separation of nano-sized particles.
The weaker effect of ultraviolet radiation is evidently partly due to its known low penetration or to be caused by the effect of photons to induce mobility of small particles.
.Microfibrils and secondarily formed fibrils continue to assimilate and grow during the input of external energy and even after it, duration depending on the amount energy fed, temperature, local concentration of nano-sized particles, and viscosity of the medium.
After being ended, it can be restarted by restarting illumination, heat or solvent treatment.
Secondary fibrils can have diameters of 200 to 600 nm. The length of chains is often higher than 50 gm, the highest dimensions observed have been 5 mm.
Accordingly, length to diameter ratios are thus at least 80.
Aerosol formed in dry state is in a fibrous material partly absorbed in pores, partly directed outside. Correspondingly, when the material to be treated is suspended in a liquid medium, particles released by heating or light radiation move and behave similarly, however depending on the viscosity of the medium. In treatments with water
Without binding to any possible mechanism, the observations given in the paragraph above indicate, that the key mechanism of this method is removal of bound water from plant tissues or accumulations contaning nanocellulose or its precursors. It is commonly known, that removal of the residual moisture, about 2%, from lignocellulosic materials is extremely difficult using conventional drying methods. Nanocellulose is commonly known to have high water retention capacity. Prolonged heating, infrared radiation, microwave radiation and water soluble organic solvents, have each a good ability to water removal and have now been found to induce separation of nano-sized particles.
The weaker effect of ultraviolet radiation is evidently partly due to its known low penetration or to be caused by the effect of photons to induce mobility of small particles.
.Microfibrils and secondarily formed fibrils continue to assimilate and grow during the input of external energy and even after it, duration depending on the amount energy fed, temperature, local concentration of nano-sized particles, and viscosity of the medium.
After being ended, it can be restarted by restarting illumination, heat or solvent treatment.
Secondary fibrils can have diameters of 200 to 600 nm. The length of chains is often higher than 50 gm, the highest dimensions observed have been 5 mm.
Accordingly, length to diameter ratios are thus at least 80.
Aerosol formed in dry state is in a fibrous material partly absorbed in pores, partly directed outside. Correspondingly, when the material to be treated is suspended in a liquid medium, particles released by heating or light radiation move and behave similarly, however depending on the viscosity of the medium. In treatments with water
7 soluble organic solvents, nano-sized particles and subsequently microfibrils and secondary fibrils are for their main part separated or are formed instantaneously.
Ingredients found advantageous for the purpose are cellulose fibrils which are separated from fibres, are in damaged fibres, and/or have been treated by chemical or enzymatic means to remove layers of protecting materials. Rich sources of separate fibrils or fibrils which react strongly to effects of light, heat or solvents are, among others, straw cellulose, maize cobs, and recirculated paper or tissue paper containing it.
Furthermore, transparent sheets appearing in strongly fibrillated cellulose are networks of nanofibrils. They are disintegrated in treatments according to this method to submicroscopic particles forming said precursors. In selecting materials, hygienic and other purity requirements, including possible thermal or light influenced reactions of other components of the mixture, have to be regarded, depending of the application.
Precipitated thin layers can be amorphic and can remain in this state for months.
Transforming to microfibril structures, clusters, secondary fibrils or networks is enhanced by moisture and/or additional energy or solvent treatmens. Particles and clusters of nanocellulose and its precursors present in a feedstock, such as maize cob, recirculated fibre or tissue paper containing it can be separated to precursors and then accumulated to microfibrils, their clusters or thin transparent foils by light, thermal energy or by solvent treatments.
Suspensions containing particles of the same magnitude as in aerosols can be made in liquid media such as organic solvents or ingredients of plastics, rubbers or paints.
Combining with other ingredients can be, for example, impregnating a pre-treated cellulosic material as such or combined with fibres or fibrils of other materials with such media and performing a heat or light treatment in one or several stages in this mixture. Nano-scaled particles are separated inside this mixture and form there secondary fibrils, their clusters or networks until it is prevented by hardening or other bonding. 'of the medium. Aerosol which has been formed but not bound to microfibrils flows due to local pressure differences to pores or cracks of the material and converts gradually to fibrils or their network, whereby the bonds created reinforce the structure.
These effects can be advanced by new heat or light treatments, even at lower temperatures than in previous treatments.
Ingredients found advantageous for the purpose are cellulose fibrils which are separated from fibres, are in damaged fibres, and/or have been treated by chemical or enzymatic means to remove layers of protecting materials. Rich sources of separate fibrils or fibrils which react strongly to effects of light, heat or solvents are, among others, straw cellulose, maize cobs, and recirculated paper or tissue paper containing it.
Furthermore, transparent sheets appearing in strongly fibrillated cellulose are networks of nanofibrils. They are disintegrated in treatments according to this method to submicroscopic particles forming said precursors. In selecting materials, hygienic and other purity requirements, including possible thermal or light influenced reactions of other components of the mixture, have to be regarded, depending of the application.
Precipitated thin layers can be amorphic and can remain in this state for months.
Transforming to microfibril structures, clusters, secondary fibrils or networks is enhanced by moisture and/or additional energy or solvent treatmens. Particles and clusters of nanocellulose and its precursors present in a feedstock, such as maize cob, recirculated fibre or tissue paper containing it can be separated to precursors and then accumulated to microfibrils, their clusters or thin transparent foils by light, thermal energy or by solvent treatments.
Suspensions containing particles of the same magnitude as in aerosols can be made in liquid media such as organic solvents or ingredients of plastics, rubbers or paints.
Combining with other ingredients can be, for example, impregnating a pre-treated cellulosic material as such or combined with fibres or fibrils of other materials with such media and performing a heat or light treatment in one or several stages in this mixture. Nano-scaled particles are separated inside this mixture and form there secondary fibrils, their clusters or networks until it is prevented by hardening or other bonding. 'of the medium. Aerosol which has been formed but not bound to microfibrils flows due to local pressure differences to pores or cracks of the material and converts gradually to fibrils or their network, whereby the bonds created reinforce the structure.
These effects can be advanced by new heat or light treatments, even at lower temperatures than in previous treatments.
8 Preparation of an aerogel-like thin aerosol layer is most simply performed by treating a cellulose-based starting material by heat, light, other electromagnetic energy , and allowing the resulting aerosol to flow towards a selected surface, as such or after removal of water and fragments of the starting material by methods known as such.
Fixing can be, for instance, by precipitation, adsorption or electrostatic means. For improving the stability of the layer it is advantageous to use a starting material from which fmely divided fibrils can be separated and mixed in the aerosol flow, to support the structure. A tight aerosol layer can be converted to secondary fibrils or their clusters by using some of the said forms of energy.
Alternatively, aerosol is formed in a porous cellulosic material, extracted from it with a water-soluble organic solvent, and the suspension is applied to a selected surface where the solvent is evaporated. This allows an even and controllable thickness of the nano-sized material. Both of these alternatives can be used for production of thin nanocellulose layers to be used for electrical, electronic or medical applications.
Application of nanofibrils formed for reinforcing composites, paper or cardboard is most advantageous in combination of cellulosic or other macro-scale fibres.
Microfibrils and secondary fibrils formed are found to crosslink cellulosic fibres and fibrils thus reinforcing the mechanical structure and also altering the permeability and surface properties. An advantage of this method is that nanocellulose is formed inside the material to be reinforced, whereby a too early agglomeration with other nano-sized particles is avoided.
In composites, the binding material is most often hydrophobic. When precursors are emitted, they have an immediate contact with this medium, and the hydrophobic tails ensure integration in it. As a result, also microfibrils and secondary fibrils formed have this immediate contact. No crevices separating fibrils from the binding medium have been observed by optical microscopy. Another advantage is the growth of these fibrils inside the binding medium to dimensions and length to diameter ratios which are needed for improving mechanical properties. Preconditions to allow or enhance the growth of secondary fibrils sufficiently are an applicable viscosity, temperature and time before hardening. Addition of nanocellulose containing ingredients to the
Fixing can be, for instance, by precipitation, adsorption or electrostatic means. For improving the stability of the layer it is advantageous to use a starting material from which fmely divided fibrils can be separated and mixed in the aerosol flow, to support the structure. A tight aerosol layer can be converted to secondary fibrils or their clusters by using some of the said forms of energy.
Alternatively, aerosol is formed in a porous cellulosic material, extracted from it with a water-soluble organic solvent, and the suspension is applied to a selected surface where the solvent is evaporated. This allows an even and controllable thickness of the nano-sized material. Both of these alternatives can be used for production of thin nanocellulose layers to be used for electrical, electronic or medical applications.
Application of nanofibrils formed for reinforcing composites, paper or cardboard is most advantageous in combination of cellulosic or other macro-scale fibres.
Microfibrils and secondary fibrils formed are found to crosslink cellulosic fibres and fibrils thus reinforcing the mechanical structure and also altering the permeability and surface properties. An advantage of this method is that nanocellulose is formed inside the material to be reinforced, whereby a too early agglomeration with other nano-sized particles is avoided.
In composites, the binding material is most often hydrophobic. When precursors are emitted, they have an immediate contact with this medium, and the hydrophobic tails ensure integration in it. As a result, also microfibrils and secondary fibrils formed have this immediate contact. No crevices separating fibrils from the binding medium have been observed by optical microscopy. Another advantage is the growth of these fibrils inside the binding medium to dimensions and length to diameter ratios which are needed for improving mechanical properties. Preconditions to allow or enhance the growth of secondary fibrils sufficiently are an applicable viscosity, temperature and time before hardening. Addition of nanocellulose containing ingredients to the
9 composition has been found to elevate especially elastic modulus and impact strength.
Due to the low length dimensions, an increase of tensile strength is not found, but expected to be achieved by including long fibres in the mixture to be reinforced.
Nanocellulose and its precursors prepared by this method are applicable for use in medical devices, for example for preparation of wound dressings and some surgical implants. In addition to the cost advantage as compared to bacterial nanocellulose it has the advantage to emit nano-sized particles to the wound, to support the growth of the healing tissue. This ability can be enhanced by activating before use a wound dressing containing this nanocellulose by an energy treatment of short duration, for example one 3.0 minute, by microwave, ultraviolet or infrared treatment. The amount particles emitted during one day has been found to be less than 0.1 mg/cm2.
Potential applications are for purposes and industries mentioned in the introduction.
Procedures or principles of some typical applications are given in Examples, and subject to be optimized depending of the starting material and particular application, and further in the Claims.
Examples Example 1. Enriching nanocellulose and precursors 8.8 g of paper produced from oat straw cellulose prepared according to United States Patent n:o 8,956,522 (Cerefi Ltd, 18 April 2006) was pulped in 400 ml of demineralized water. 100 mg of citric acid was added for complexing potentially remaining divalent cations, whereby pH was lowered to 5.5. 0.5 ml of pectinase enzyme (Biotouch PL 300, AB Enzymes, Rajamaki, Finland) was added. The mixture was incubated at 50 C for 90 minutes, and homogenized with a blade mixer.
Subsequently the mixture was subjected to two freezing-thawing cycles to disintegrate the cellular structure. 1 ml of household tenside mixture (Nopa A/S, Denmark) was added, the mixture foamed by stirring, and dried in microwave oven by 700 W
effect in six subsequent 30 sec periods. In the enriched product, clusters of visible precursors were microscopically discernible. The product, as such or omitting some of the steps given, as sheets or ground, can be used as an ingredient or intermediate, to be activated to nanocellulose or microfibrils within the product of an application, by energy sources or solvents given in the description.
Example 2. Microfibril thin layers on solid surfaces 5 A sample of the enriched nanoprecursor preparation according to Example 1 was illuminated with microscope lamp of 100 W, the light was focused to an area of 7 mm2 After ca 30 seconds, disintegration producing aerosol started emitting nano-scaled particles. Flow of aerosol was directed to a glass plate placed 2 or 3 mm above the illuminated material. Thin film developed on the glass plate 3 mm above the illuminated
Due to the low length dimensions, an increase of tensile strength is not found, but expected to be achieved by including long fibres in the mixture to be reinforced.
Nanocellulose and its precursors prepared by this method are applicable for use in medical devices, for example for preparation of wound dressings and some surgical implants. In addition to the cost advantage as compared to bacterial nanocellulose it has the advantage to emit nano-sized particles to the wound, to support the growth of the healing tissue. This ability can be enhanced by activating before use a wound dressing containing this nanocellulose by an energy treatment of short duration, for example one 3.0 minute, by microwave, ultraviolet or infrared treatment. The amount particles emitted during one day has been found to be less than 0.1 mg/cm2.
Potential applications are for purposes and industries mentioned in the introduction.
Procedures or principles of some typical applications are given in Examples, and subject to be optimized depending of the starting material and particular application, and further in the Claims.
Examples Example 1. Enriching nanocellulose and precursors 8.8 g of paper produced from oat straw cellulose prepared according to United States Patent n:o 8,956,522 (Cerefi Ltd, 18 April 2006) was pulped in 400 ml of demineralized water. 100 mg of citric acid was added for complexing potentially remaining divalent cations, whereby pH was lowered to 5.5. 0.5 ml of pectinase enzyme (Biotouch PL 300, AB Enzymes, Rajamaki, Finland) was added. The mixture was incubated at 50 C for 90 minutes, and homogenized with a blade mixer.
Subsequently the mixture was subjected to two freezing-thawing cycles to disintegrate the cellular structure. 1 ml of household tenside mixture (Nopa A/S, Denmark) was added, the mixture foamed by stirring, and dried in microwave oven by 700 W
effect in six subsequent 30 sec periods. In the enriched product, clusters of visible precursors were microscopically discernible. The product, as such or omitting some of the steps given, as sheets or ground, can be used as an ingredient or intermediate, to be activated to nanocellulose or microfibrils within the product of an application, by energy sources or solvents given in the description.
Example 2. Microfibril thin layers on solid surfaces 5 A sample of the enriched nanoprecursor preparation according to Example 1 was illuminated with microscope lamp of 100 W, the light was focused to an area of 7 mm2 After ca 30 seconds, disintegration producing aerosol started emitting nano-scaled particles. Flow of aerosol was directed to a glass plate placed 2 or 3 mm above the illuminated material. Thin film developed on the glass plate 3 mm above the illuminated
10 cellulose sample had a homogenous and oriented network of rnicrofibrils and was substantially free from solid fragments of the starting material, whereas such fragments were occasionally found on the glass plate 2 mm above the sample. Covering the glass plate with polyethene foil resulted collection of a similar network on this flexible material. This principle can be scaled up to larger batch or continuous productions for purposes of electrical and electronic industries and for production of medical devices.
Example 3. Effect on mechanical and surface properties of paper From oat fibre cellulose prepared according to U.S. Patent n:o 8,956,502, paper sheets of 35 g/m2 were prepared. When treated, they were in equilibrium with 38% air humidity. Test sheets were subjected to ultraviolet light (Omnilux R 80 75 W, omnilux ¨lamps.com), infrared light (Sylvania Infra-red 100 W, havells-sylvania.com) or microwave (700 W) irradiation, or immersion in 100 % ethanol. Each treatment lasted for 60 seconds. Energy transferred at ultraviolet light or microwave treatments corresponded to 1.57 kWh/kg, and in infrared light treatment 2.09 kWh/kg of the paper.
Under these conditions, treatments other than ultraviolet light resulted a similar development of microfibril network, crosslinking cellulosic fibres and fibrils of the paper. The effect of ethanol was the most rapid. After microwave treatment, elastic modulus of the paper, equilibrated to 50% air humidity, was measured. After one hour from treatment, no significant change from the starting value was observed.
During 24 hours from the treatment, the elastic modulus elevated from initial value of 2.24 (}Pa to 15.34 GPa. With ultraviolet light, a thick aerosol was developed on and above the
Example 3. Effect on mechanical and surface properties of paper From oat fibre cellulose prepared according to U.S. Patent n:o 8,956,502, paper sheets of 35 g/m2 were prepared. When treated, they were in equilibrium with 38% air humidity. Test sheets were subjected to ultraviolet light (Omnilux R 80 75 W, omnilux ¨lamps.com), infrared light (Sylvania Infra-red 100 W, havells-sylvania.com) or microwave (700 W) irradiation, or immersion in 100 % ethanol. Each treatment lasted for 60 seconds. Energy transferred at ultraviolet light or microwave treatments corresponded to 1.57 kWh/kg, and in infrared light treatment 2.09 kWh/kg of the paper.
Under these conditions, treatments other than ultraviolet light resulted a similar development of microfibril network, crosslinking cellulosic fibres and fibrils of the paper. The effect of ethanol was the most rapid. After microwave treatment, elastic modulus of the paper, equilibrated to 50% air humidity, was measured. After one hour from treatment, no significant change from the starting value was observed.
During 24 hours from the treatment, the elastic modulus elevated from initial value of 2.24 (}Pa to 15.34 GPa. With ultraviolet light, a thick aerosol was developed on and above the
11 glossy surface adjacent to the light source, and was sedimenthig slowly. After ultraviolet light treatment, no change in elastic modulus was found in 10 days. The difference has most probably been due to concentrating the effect on the surface, due to the lower penetration of the ultraviolet light, and by absence of any thermal effect, which with the other treatments had effected removal of residual moisture and consequently higher release of nano-scaled particles. The treatments effected a more dense fibrillar network, and a more smooth surface.
Example 4. Effect on mechanical properties of a composite From oat cellulose prepared according to United States Patent n:o 8,956,502, paper sheets of 102 g/m2 were prepared and wet laminated in four layers in a vacuum sack equipmet with Ashland Envirez polyester. Weight percentage of cellulose in the composite was 65%, curing time 12 hours at 80 C. Thickness of the resulting composite sheet was 1.1 mm. Flexural strength of the composite was 102 MPa, and flexural modulus 5.1 GPa. Corresponding values for polycondensed resin without fibre were 33.8 MPa and 3.0 GPa, respectively. Microscopic evaluation indicated that a part of the cellulosic material was converted to microfibrils and secondary fibrils during curing.
Example 5. Preparations for burn and wound healing Oat straw paper was prepared as described in United States Patent No 8,956,522, foam dried as described in Example 1, and activated by heating at 130 C for 90 minutes. The product was tested for healing a bum wound of 70 mm in length, 5 mm broad, and 0.5 to 2 mm deep in an arm of a male patient. The product was placed on the wound when it started to exude liquid, and was removed after 12 hours. 24 days after the injury, microscopic study of surface samples of the healed skin revealed microfibrils mixed in the healed tissue indicating that aerosol from the product had integrated in it and supported the growth of the healing tissue. Within 6 months from the injury, no scar was formed, and also the surface pattern of the skin on the site of injury was similar to the skin nearby.
Example 4. Effect on mechanical properties of a composite From oat cellulose prepared according to United States Patent n:o 8,956,502, paper sheets of 102 g/m2 were prepared and wet laminated in four layers in a vacuum sack equipmet with Ashland Envirez polyester. Weight percentage of cellulose in the composite was 65%, curing time 12 hours at 80 C. Thickness of the resulting composite sheet was 1.1 mm. Flexural strength of the composite was 102 MPa, and flexural modulus 5.1 GPa. Corresponding values for polycondensed resin without fibre were 33.8 MPa and 3.0 GPa, respectively. Microscopic evaluation indicated that a part of the cellulosic material was converted to microfibrils and secondary fibrils during curing.
Example 5. Preparations for burn and wound healing Oat straw paper was prepared as described in United States Patent No 8,956,522, foam dried as described in Example 1, and activated by heating at 130 C for 90 minutes. The product was tested for healing a bum wound of 70 mm in length, 5 mm broad, and 0.5 to 2 mm deep in an arm of a male patient. The product was placed on the wound when it started to exude liquid, and was removed after 12 hours. 24 days after the injury, microscopic study of surface samples of the healed skin revealed microfibrils mixed in the healed tissue indicating that aerosol from the product had integrated in it and supported the growth of the healing tissue. Within 6 months from the injury, no scar was formed, and also the surface pattern of the skin on the site of injury was similar to the skin nearby.
Claims (26)
1. A method for production and use of nanocellulose, its precursors, concentrates and products containing nanocellulose, characterized by, that nanometer-sized particles are separated from fibrils of cellulosic material by treating it by means of light, controlled heating or a water-soluble organic solvent.
2. A method according to claim 1, characterized by, that the light source is visible or infrared light.
3. A method according to claim 1, characterized by, that the light source is ultraviolet light.
4. A method according to claim 1, characterized by, that heat treatment is performed at temperatures not exceeding 180°C.
5. A method according to claim 1. characterized by, that heating is performed by feeding heat producing electromagnetic energy.
6. A method according to one of the preceding Claims, characterized by, that the treatment is effected by removal of bound water.
7. A method according to Claim 6, characterized by, that removal of bound water is effected by water-solube organic solvents.
8. A method according to one of the preceding Claims, characterized by, that the material to be treated consists of parts or constituents of non-woody plants.
9. A method according one of the preceding Claims, characterized by, that the material to be treated is recirculated cellulosic fibre or cellulosic material containing it.
10. A method according to one of the preceding Claims, characterized by, that the cellulosic material is pretreated with hemicellulose or pectin decomposing enzymes.
11. A method according to one of the preceding Claims, characterized by, that the cellulosic material is pretreated by freezing and thawing cycles.
12. A method according to one of the previous Claims, characterized by, that nanometere-scaled particles are separated in dry state as aerosol, and in a liquid medium as a suspension.
13. A method according to one of the preceding Claims, characterized by, that nanometre-scaled particles are combined to each other forming chains, elementary fibrils, microfibrils, secondarily formed fibrils and networks of these.
14. A method according to one of the preceding Claims, characterized by, that separation of the nano-scaled particles and their combination continues also after the treatment with energy or water-removing solvent has ended.
15. A method according to one of the preceding Claims, characterized by, that microfibrils, secondary fibrils or their network crosslink cellulosic fibres or fibrils.
16. A method according to one of the preceding Claims, characterized by, that the aerosol separated is attached to a solid surface forming thin layers of microfibrils.
17. A method according to one of the preceding Claims, characterized by, that the aerosol separated is attached to porous materials filling pores or cracks with a network of microfibrils.
18. A method according to one of the preceding Claims, characterized by, that separation of nano-scaled particles and subsequent stages are performed in dry or air-dry (having moisture content which is in equilibrium with air humidity) cellulose material.
19. A method according to Claim 18, characterized by, that it is used for affecting mechanical and surface properties and fibre network of paper or cardboard.
20. A method according to one of the preceding Claims, characterized by, that separation of nano-scaled particles and subsequent stages from cellulosic material are performed when it is suspended in a liquid medium.
21. A method according to Claim 20, characterized by, that the liquid medium consists of ingredients of composite or paint materials.
22. A method according to one of the preceding Claims, characterized by, that secondary fibrils having length of 50 µm or higher are formed from nano-sized particles.
23. A method according to one of the preceding Claims, characterized by, that secondary fibrils with length to diameter ratio of 80 or higher are formed from nano-sized particles.
24. A method according to one of the preceding Claims, characterized by, that nano-sized particles and secondary fibrils are formed in composite binding material before its hardening..
25. A method according to one of the preceding Claims, characterized by, that nano-sized particles are bound with the binding material of a composite immediately without any separating crack or crevice.
26. A product for treating wounds or burns, characterized by, that the dressing material contains nanocellulose or its precursors and emits as such or after activation by light, controlled heating or water-soluble organic solvent nanocellulose or its precursors to the wound surface.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI20140067A FI129421B (en) | 2014-03-12 | 2014-03-12 | Production and use of nanocellulose and its precursors |
FI20140067 | 2014-03-12 | ||
PCT/FI2015/000009 WO2015136147A1 (en) | 2014-03-12 | 2015-03-11 | Method for production and use of nanocellulose and its precursors |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2942188A1 true CA2942188A1 (en) | 2015-09-17 |
Family
ID=54070988
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA2942188A Abandoned CA2942188A1 (en) | 2014-03-12 | 2015-03-11 | Method for production and use of nanocellulose and its precursors |
Country Status (8)
Country | Link |
---|---|
US (1) | US10273632B2 (en) |
EP (1) | EP3117038A4 (en) |
JP (1) | JP6522015B2 (en) |
CN (1) | CN106068347B (en) |
BR (1) | BR112016020935A8 (en) |
CA (1) | CA2942188A1 (en) |
FI (1) | FI129421B (en) |
WO (1) | WO2015136147A1 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ES2858631T3 (en) * | 2014-05-30 | 2021-09-30 | Borregaard As | Microfibrillated cellulose |
US11497837B2 (en) * | 2015-01-14 | 2022-11-15 | Innovative Plastics And Molding, Inc. | Molded parts with thermoplastic cellulose biopolymer compositions having oriented fibers for medical devices and implants |
JP6772018B2 (en) * | 2015-10-06 | 2020-10-21 | チカミミルテック株式会社 | A method for producing ultrafine fibers suitable for ultrafineness, a method for producing ultrafine fibers, ultrafine fibers suitable for ultrafineness, and ultrafine fibers. |
JP6755315B2 (en) * | 2015-12-31 | 2020-09-16 | テクノロギアン トゥトキムスケスクス ヴェーテーテー オイ | How to make films from high-consistency enzyme fibrillated nanocellulose |
EP3228329B1 (en) * | 2016-04-06 | 2022-06-08 | UPM-Kymmene Corporation | A method for preparing a medical product comprising nanofibrillar cellulose and a medical product |
US10277147B2 (en) * | 2016-06-09 | 2019-04-30 | Wisconsin Alumni Research Foundation | Triboelectric nanogenerators based on chemically treated cellulose |
US10287366B2 (en) | 2017-02-15 | 2019-05-14 | Cp Kelco Aps | Methods of producing activated pectin-containing biomass compositions |
CN112940140B (en) * | 2021-01-29 | 2022-03-11 | 中国石油大学(华东) | Method for preparing super-air-wet nano microcrystalline cellulose by one-step method and application |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11315473A (en) * | 1998-04-27 | 1999-11-16 | Rengo Co Ltd | Production of disaggregated modified cellulose-based filament |
JP3805654B2 (en) * | 2001-08-29 | 2006-08-02 | 株式会社ネクスト | Fine particles of biopolymers that prevent hemostasis and adhesion |
BRPI0612006B1 (en) * | 2005-06-28 | 2017-11-14 | Kemira Oyj | Method of preparation of microfibrillar cellulose |
JP2008075214A (en) * | 2006-09-21 | 2008-04-03 | Kimura Chem Plants Co Ltd | Method for producing nanofiber and nanofiber |
JP5404131B2 (en) * | 2009-03-30 | 2014-01-29 | 日本製紙株式会社 | Method for producing cellulose nanofiber |
FI123270B2 (en) * | 2010-06-07 | 2019-04-15 | Kemira Oyj | Manufacturing of microcellulose |
JP2012111849A (en) * | 2010-11-25 | 2012-06-14 | Oji Paper Co Ltd | Method for producing microfibrous cellulose, method for producing microfibrous cellulose sheet, and microfibrous cellulose composite |
FI126259B (en) * | 2011-02-11 | 2016-09-15 | Upm Kymmene Corp | Microfibrillated cellulose for use in the treatment of atopic dermatitis and psoriasis |
JP5863269B2 (en) * | 2011-04-20 | 2016-02-16 | 株式会社ダイセル | Microfiber and method for producing the same |
CN102899950B (en) * | 2012-10-25 | 2015-10-14 | 福建农林大学 | A kind of ultrasonic-microwave is the auxiliary method preparing nano-cellulose simultaneously |
FI126109B (en) | 2013-02-22 | 2016-06-30 | Upm Kymmene Corp | Nanofibrillar polysaccharide for use in inhibiting and controlling lace and scar formation |
CN103421203B (en) * | 2013-08-21 | 2016-05-04 | 华南理工大学 | A kind of preparation method of nano-cellulose film of application of heat |
WO2015074120A1 (en) * | 2013-11-22 | 2015-05-28 | The University Of Queensland | Nanocellulose |
-
2014
- 2014-03-12 FI FI20140067A patent/FI129421B/en active IP Right Grant
-
2015
- 2015-03-11 US US15/121,868 patent/US10273632B2/en not_active Expired - Fee Related
- 2015-03-11 JP JP2016574495A patent/JP6522015B2/en active Active
- 2015-03-11 BR BR112016020935A patent/BR112016020935A8/en active Search and Examination
- 2015-03-11 EP EP15761903.2A patent/EP3117038A4/en not_active Withdrawn
- 2015-03-11 CN CN201580012231.7A patent/CN106068347B/en not_active Expired - Fee Related
- 2015-03-11 WO PCT/FI2015/000009 patent/WO2015136147A1/en active Application Filing
- 2015-03-11 CA CA2942188A patent/CA2942188A1/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
EP3117038A4 (en) | 2017-11-08 |
CN106068347B (en) | 2019-06-21 |
EP3117038A1 (en) | 2017-01-18 |
FI20140067L (en) | 2015-09-13 |
US10273632B2 (en) | 2019-04-30 |
WO2015136147A1 (en) | 2015-09-17 |
US20170067207A1 (en) | 2017-03-09 |
CN106068347A (en) | 2016-11-02 |
BR112016020935A2 (en) | 2018-05-15 |
JP6522015B2 (en) | 2019-05-29 |
FI129421B (en) | 2022-02-15 |
BR112016020935A8 (en) | 2022-08-16 |
JP2017510730A (en) | 2017-04-13 |
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